Method of preparing chloroacetyl chloride

ABSTRACT

A method of preparing chloroacetyl chloride which comprises reacting by contacting in the vapor phase, at a temperature of about 20* to 350* C., vinylidene chloride with O2 in the presence of a free radical initiator.

Minted States Patent [151 3,674,664

Larsen et al. July 4, 1972 54] METHOD OF PREPARING 58 Field of Search..204/l58 R, 158 HE; 260/544 Y CHLOROACETYL CHLORIDE I [56] ReferencesCited [72] Inventors: Eric R. Larsen, Midland, M1ch.; Albert KentKeller, Punta Gorda, British Hon- FOREIGN PATENTS OR APPLICATIONS was;Raymnd news 746,451 7/1944 Germany ..204/l58 [73] Assignee: The DowChemical Company, Midland,

Mi h- Primary Examiner-Howard S. Williams Attorney-Griswold and Burdick,J. Roger Lochhead and C. [22] Filed. March 6, 1970 E. Rehberg [21] Appl.No.: 17,292

[57] ABSTRACT Related U.S. Application Data I A method of preparingchloroacetyl chloride WhlCh comprises commuatlon'm'pan of O- 804,689,March 5, reacting by contacting in the vapor phase, at a temperature of1969,aband0nd- 1 about 20 to 350 0, vinylidene chloride with 0 in thepresence of a free radical initiator. [52] U.S. Cl ..204/158 R, 204/158HE, 260/544 Y [51] Int. Cl. ..B01j 1/10, C07c 51/58 11 Claims, NoDrawings METHOD OF PREPARINGCHLOROACETYL CHLORIDE This application is acontinuation-in-part of copending application, Ser. No. 804,689, filedMar. 5, 1969, now abandoned.

BACKGROUND OF THE INVENTION It is well known in the art that olefins ofthe type wherein X is a halogen, are oxidized by elemental oxygen (air)in the presence of ultraviolet light and C1 or Br to yield thecorresponding haloacetyl halide, i.e.,

However, the formation of chloroacetyl chloride from the oxidation ofvinylidene chloride is not so widely reported. Rather, the oxidation ofvinylidene chloride yields a peroxide along with polymer. R. C.Reinhardt (Industrial and Engineering Chemistry, 35, 423 (1943)),teaches that in the liquid phase the presence of large amounts of air,or oxygen, along with light, leads to the formation of abundant amountsof peroxide which separate out with the polymer, which is insoluble inthe monomer. This polymer, containing the peroxide, readily detonateswhen it is allowed to dry. Reinhardt reports also that the ultimatereaction products formed by the liquid phase oxidation of vinylidenechloride are CH O, COCl and HCl.

German Pat. No. 746,451 (published July 29, 1944) teaches a method ofproducing chloroacetyl chloride by the liquid phase oxidation ofvinylidene chloride in the presence of C1 and actinic light. The methodrequires, however, mea sures which prevent the formation of polymerscontaminated with peroxide, for the reasons outlined above, i.e.,explosions.

Therefore, the formation of chloroacetyl chloride from vinylidenechloride has not been commercialized for reasons of safety hazards inthe known processes to date.

It has now been discovered that chloroacetyl chloride can be safelyproduced by the vapor phase oxidation of vinylidene chloride.

SUMMARY OF THE INVENTION The instant invention is a method of preparingchloroacetyl chloride whichcomprises reacting by contacting in the vaporphase, at a temperature of about 20 to 350 C., vinylidene chloride withO in the presence of a free radical initiator.

A molar ratio of vinylidene chloride/O of 3/1 to 1/20 is suitable forthe process of this invention, while a ratio of III to H5 is preferred.Insufficient 0 results in low conversion of vinylidene chloride, with acorresponding decrease in yield, and increase in polymer formation.However, large excesses of 0 are not detrimental except that thethrough-put for a given reactor is decreased. Atmospheric air is alsosuitable.

The ratio of vinylidene chloride to free radical initiator is dependenton the reactivity of the radicals. Reactive radicals such as halogenatoms, alkyl radicals and the like are effective in lower concentrationsthan relatively stable radicals, such as N0 In general, higherconcentrations of radicals will facilitate reaction while lowconcentrations of radicals or radical precursors will be less effective.Likewise, the contact time of radicals with the reacting system(vinylidene chloride-oxygen) will afiect conversion. A short contacttime will be detrimental to yield, whereas long contact times willincrease yield with the additional possibility of forming by-products bythe reaction of radicals with the product, chloroacetyl chloride. Thecontact time can be easily optimized by varying the rate of input ofstarting materials into the reactor while monitoring conversion ofvinylidene chloride and yield of chloroacetyl chloride.

While temperatures of reaction of about 20 to 350 C. are suitable forthis invention, to 200 C. is preferred. As is generally expected invapor phase reactions, increasing pressure increases the eflectivethrough-put of the reactor. While atmospheric pressure is convenient,two or three atmospheres pressure will increase the rate of reactionsubstantially.

All the common free radical initiators are generally suitable for themethod of this invention. Exemplary of these initiators are halogens,such as C1 Br F and I mixtures of halogens, such as C1; Br and halogencompounds, such as ClF and BrCl. It is necessary to utilize ionizingradiation (1.R.), such as ultraviolet wavelengths, with C1 Br and 1Further examples of suitable initiators include phosgene plus I.R.; CC],plus I.R.; BrCCl plus 1.R.; N0 NO; and ionizing radiation alone,including gamma, beta and X-rays.

The method taught herein can suitably be run in a batch or continuousfashion. A continuous reaction is preferable.

SPECIFIC EMBODIMENTS The reactions were conducted by metering vapors ofvinylidene chloride (V in table headings) into a suitable reactor.Oxygen and free radicals or free radical precursors were metered asvapors into the same reactor either separately or premixed. Whenionizing radiation was used as an initiator (see Example 10 below), itwas not necessary to have an additional source of free radicals apartfrom the vinylidene chloride and oxygen, although it may be advantageousto do so (see Example llbelow). The temperature in the reaction zone,except for Examples 10-12, was determined by means of thermocouplesplaced inside sealed wells in the reactor.

The reactor for Examples 1, 2 and 4 (below) consisted of a Pyrex glasstube approximately 35 cm. long and 3 cm. i.d. This tube had provisionsfor cooling with circulating cold water in an outer glass jacket andinternal glass coils. Provisions were made for admitting vinylidenechloride and a mixture of oxygen and halogen through two 4 mm. id. inlettubes at the bottom of the reactor. The product condensed was taken outthe bottom of the reactor, while the unreacted gases were vented throughthe top of the reactor to a separate condenser. 1rradiation was providedby three 275 watt sunlamps along the length of the reactor producinglight of 3,000 A. and longer wavelength (I11 The total volume of thisreactor was approximately 025 liters which, knowing the totalthrough-put of starting materials in moles or liters per hour, allowedcalculation of the approximate residence time in the reactor.

In Example 3, the reactor was of the same design except that the innerdiameter and length were expanded to 14 cm. and 76 cm., respectively.This reactor had a vapor space of approximately 5.8 liters. Irradiationwas provided by a 2,000 watt medium pressure mercury arc lamp placed ina Pyrex well along the length in the center of the reactor.

For Examples 6 to 9 below, the reactor, approximately 0.25 litersvolume, was lacking the outer cooling jacket. The starting materialswere admitted through the top of the reactor and the vapor and liquidwere vented and separated at the bottom. Irradiation in Example 6 wasprovided by a 450 watt medium pressure mercury arc lamp placedvertically and parallel to the reactor about 4 inches away.

In Examples 7 and 8 the reactor consisted of a straight tube, 2 cm. indiameter and 45 cm. long. The reactor was heated to the temperatureshown by means of three infrared heating lamps. The reactants wereadmitted as vapors at the top of the reactor and condensible productsand starting materials were collected at the bottom. Irradiation wasprovided as in Example 6.

In Example 5 the reactor consisted of a water-jacketed tube 1.5 cm. by50 cm. long. The halogen-oxygen-nitrogen mixture was admitted along thelength of a glass tube fitted inside and in the upper half of thereactor, said tube being 0.5 cm. in diameter, 25 cm. long and containingpinholes approximately 1 mm. in diameter at 1 cm. intervals upwards fromthe closed bottom. The vinylidene chloride was admitted as a vapor atthe top of the reactor and allowed to difiuse downward along the halogeninlet tube. The products were collected at the bottom and unreactedvapors were vented. C11 is capable of igniting vinylidenech1oride-oxygen mixtures in the absence of sufficient cooling area.Nitrogen (7.7 moles/hr.) was used as a diluent to moderate the reaction.

In Examples -12 the reactor consisted of a stainless steel pipe 5 cm. by30.5 cm. capped at the top with a 0.002 inch thick sheet of nickel. Thevinylidene chloride vapor and oxygen, or oxygen and chlorine, weremetered in through two fittings just below the top of the reactor. Theliquid and gaseous product mixture was vented through a fitting in thebottom cap of the pipe reactor. The vented mixture was led to a glasscondenser where liquid and vapor separation was effected. This reactorhad copper tubing coils wrapped around the outside through which water(60 C.) was circulated The reactor was placed beneath a beam of ionizingradiation which entered through the nickel cover.

Analysis was by vapor phase chromatography in all cases.

l. in the process of preparing chloroacetyl chloride which comprisesreacting by contacting, at a temperature of about to 350 C., vinylidenechloride with O in the presence of a free radical initiator, theimprovement of carrying out said process in the vapor phase.

2. The process of claim 1 wherein said process is conducted at apressure of up to three atmospheres.

3. The process of claim 1 wherein the process is a continuous one.

10 4. The process of claim 2 wherein the initiator is phosgene plusionizing radiations.

5. The process of claim 2 wherein the initiator is ionizing radiation.

6. The process of claim 2 wherein the initiator is C112,.

7. The process of claim 2 wherein the initiator is F 8. The process ofclaim 2 wherein the initiator comprises a halogen plus ionizingradiation.

9. The process of claim 3 wherein the halogen is C1 10. The processofclaim 3 wherein the halogen is Br 11. The process ofclaim 3 whereinthe halogen is l.

TABLE V in. C.A.C. conv.m.perc ent Example V 0;, Catalyst. Temp., Numberm./hr. m./hr. Catalyst m./hr.

1. 96 1. T2 Bra-Hi 0. 34 108 1. 96 0. 34 110 21. 6 0. 48 122 1. 96 1 380. 18 Brz- 110 tion. 2. 0 1. 5 Cl: plus ionizing Gi -0.34 60 radiation.12 2.0 1.5 Ci; plus ionizing Gig-0.34 60 radiation"'.

82. 5 None.

J 100 Do. 20 100 Do. 5. 5 71 29% unidentified product. 57. 4 100 None.

74.8 80. 2 19.8% 1,1,1,Z-tetracldoroethane.

10. 8 9. 3 90.7% 1,1,1,2-tctraehloroethane.

chloroacetyl chloride. 100 #8 of 2 mev. electrons from a Van de Graafigenerator.

' Radiation produced by bombarding tungsten target with 2 mev. electronbeam of 250 a.

We claim:

2. The process of claim 1 wherein said process is conducted at apressure of up to three atmospheres.
 3. The process of claim 1 whereinthe process is a continuous one.
 4. The process of claim 2 wherein theinitiator is phosgene plus ionizing radiations.
 5. The process of claim2 wherein the initiator is ionizing radiation.
 6. The process of claim 2wherein the initiator is ClF3.
 7. The process of claim 2 wherein theinitiator is F2.
 8. The process of claim 2 wherein the initiatorcomprises a halogen plus ionizing radiation.
 9. The process of claim 3wherein the halogen is Cl2.
 10. The process of claim 3 wherein thehalogen is Br2.
 11. The process of claim 3 wherein the halogen is I2.